U.S. patent number 11,109,947 [Application Number 15/305,952] was granted by the patent office on 2021-09-07 for method for performing an optical three-dimensional recording.
This patent grant is currently assigned to DENTSPLY SIRONA Inc.. The grantee listed for this patent is SIRONA DENTAL SYSTEMS GMBH. Invention is credited to Anders Adamson, Tom Bobach, Nico Grund.
United States Patent |
11,109,947 |
Adamson , et al. |
September 7, 2021 |
Method for performing an optical three-dimensional recording
Abstract
The invention relates to a method for performing an optical
three-dimensional recording by using hand-held dental camera. The
camera automatically records a plurality of individual optical
recordings in succession at a defined frequency during the
measurement. The individual three-dimensional optical recordings
are combined into an overall recording of a dental object to be
measured and before the measurement is performed, a
three-dimensional standard jaw model is displayed using a display
device and a first control point on the standard jaw model is
displayed using the display device. The hand-held dental camera is
then positioned in relation to the object to be recorded in such a
way that the camera points at the first control point of the
standard jaw model and records a corresponding recording region of
the dental object.
Inventors: |
Adamson; Anders (Darmstadt,
DE), Bobach; Tom (Bensheim, DE), Grund;
Nico (Heppenheim, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
SIRONA DENTAL SYSTEMS GMBH |
Bensheim |
N/A |
DE |
|
|
Assignee: |
DENTSPLY SIRONA Inc. (York,
PA)
|
Family
ID: |
1000005789122 |
Appl.
No.: |
15/305,952 |
Filed: |
April 23, 2015 |
PCT
Filed: |
April 23, 2015 |
PCT No.: |
PCT/EP2015/058767 |
371(c)(1),(2),(4) Date: |
October 21, 2016 |
PCT
Pub. No.: |
WO2015/162199 |
PCT
Pub. Date: |
October 29, 2015 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20170056136 A1 |
Mar 2, 2017 |
|
Foreign Application Priority Data
|
|
|
|
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Apr 23, 2014 [DE] |
|
|
10 2014 207 667.6 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
1/00039 (20130101); A61B 1/00055 (20130101); A61C
9/0073 (20130101); A61B 1/045 (20130101); A61B
1/00009 (20130101); A61B 1/00045 (20130101); A61B
1/24 (20130101); A61C 9/0053 (20130101) |
Current International
Class: |
A61C
9/00 (20060101); A61B 1/00 (20060101); A61B
1/045 (20060101); A61B 1/24 (20060101) |
Field of
Search: |
;433/24,29,215 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
2008537494 |
|
Sep 2008 |
|
JP |
|
2012066072 |
|
Apr 2012 |
|
JP |
|
2012157692 |
|
Aug 2012 |
|
JP |
|
2014027026 |
|
Feb 2014 |
|
WO |
|
Other References
International Search Report; PCT/EP2015/058767; Jul. 29, 2015
(completed); dated Aug. 2015. cited by applicant .
Written Opinion of the International Searching Authority;
PCT/EP2015/058767; Jul. 29, 2015 (completed); dated Aug. 12, 2015.
cited by applicant .
International Preliminary Report on Patentability;
PCT/EP2015/058767; Jul. 29, 2015 (completed); dated Aug. 12, 2015.
cited by applicant.
|
Primary Examiner: Johanas; Jacqueline T
Assistant Examiner: Belk; Shannel Nicole
Attorney, Agent or Firm: DENTSPLY SIRONA Inc.
Claims
The invention claimed is:
1. A method of recording three-dimensional images of a physical jaw
using a dental camera, comprising: displaying a virtual
three-dimensional standard jaw model corresponding to the physical
jaw on a display device; displaying a first and a second virtual
control point on a first and second virtual tooth of the virtual
three-dimensional standard jaw model respectively; determining a
virtual recording path disposed between two virtual teeth, said
virtual recording path disposed between two virtual teeth is
defined by a visible path disposed between the first virtual
control point on the first virtual tooth and the second virtual
control point on the second virtual tooth, the first virtual tooth
is different from the second virtual tooth; displaying said virtual
recording path disposed between two virtual teeth on the virtual
three-dimensional standard jaw model; operating the camera to
automatically generate a plurality of three-dimensional images of
the physical jaw in succession along portions of the physical jaw
corresponding to the virtual recording path, by moving the dental
camera relative to the physical jaw and automatically recording the
plurality of three-dimensional images at a constant frequency, the
automatic recording at the constant frequency starts from a portion
of the physical jaw corresponding to the first virtual tooth,
follows a direction of the virtual recording path, and ends at
another portion of the physical jaw corresponding to the second
virtual tooth.
2. The method according to claim 1, wherein the dental camera is
positioned over an area of a full upper jaw and/or a lower jaw.
3. The method according to claim 1, further comprising acquiring at
least one of occlusal, lingual or palatal and buccal measurements
by acquiring a plurality of individual optical recordings in an
occlusal, lingual or palatal and buccal parts of physical jaw and
registering the plurality of individual optical recordings into an
overall three-dimensional recording using a registration
process.
4. The method according to claim 1, wherein the virtual recording
path disposed between two virtual teeth runs through tooth centers
of individual virtual teeth of the virtual three-dimensional
standard jaw model.
5. The method according to claim 1, further comprising confirming a
position of the first and/or second virtual control points
displayed on the virtual three-dimensional standard jaw model by
(i) actuating a button on the dental camera, (ii) performing a
gesture with the dental camera, (iii) providing a voice command,
and/or (iv) providing a command through an input device.
6. The method according to claim 1, wherein the first and second
virtual control points are determined on the first and second
virtual teeth respectively in an occlusal area of the virtual
three-dimensional standard jaw model, and the virtual recording
path disposed between two virtual teeth is disposed between the
first and second virtual control points in the occlusal area, such
that the occlusal measurement is performed on the physical jaw in
an occlusal direction of the physical jaw in a manner that follows
the direction of the virtual recording path disposed between two
virtual teeth.
7. The method according to claim 1, wherein the first and second
virtual control points are determined on the first and second
virtual teeth respectively in a lingual or palatal area of the
virtual three-dimensional standard jaw model, and the virtual
recording path disposed between two virtual teeth is disposed
between the first and second virtual control points in the lingual
or palatal area, such that the lingual or palatal measurement is
performed on the physical jaw in a lingual or palatal direction of
the physical jaw in a manner that follows the direction of the
virtual recording path disposed between two virtual teeth.
8. The method according to claim 1, wherein the first and second
virtual control points are determined on the first and second
virtual teeth respectively in a buccal area of the virtual
three-dimensional standard jaw model, and the virtual recording
path disposed between two virtual teeth is disposed between the
first and the second virtual control points in the buccal area,
such that the buccal measurement is performed on the physical jaw
in a buccal direction of the physical jaw in a manner that follows
the direction of the virtual recording path disposed between two
virtual teeth.
9. The method according to claim 8, wherein another first and
another second virtual control points are determined on another
first and second virtual teeth respectively in another buccal area
of the virtual three-dimensional standard jaw model, and another
virtual recording path disposed between another two virtual teeth
is disposed between the first and the another second virtual
control points in the another buccal area, such that another buccal
measurement is performed on the physical jaw in another buccal
direction of the physical jaw, in a manner that follows the
direction of the virtual recording path disposed between two
virtual teeth and wherein the buccal measurement and the another
buccal measurement are registered together using a shared
overlapping area.
10. The method according to claim 1, wherein the first and second
virtual control points are determined on the first and second teeth
respectively in a further buccal or labial area of the virtual
three-dimensional standard jaw model, and the virtual recording
path disposed between two virtual teeth is disposed between the
first and the second virtual control points in the further buccal
or labial area, such that a further buccal or labial measurement is
performed on the physical jaw in a further buccal or labial
direction perpendicular to a jaw curve of a jaw arch and wherein
the recording includes at least one fringe recording sequence that
includes fringe projections.
11. The method according to claim 1, wherein the first virtual
control point is located on a first virtual three-dimensional model
of an upper jaw and the second virtual control point is located on
a second virtual three-dimensional model of a lower jaw and the
virtual recording path disposed between two virtual teeth is
determined such that the first virtual three-dimensional model of
the upper jaw is registered with the second three-dimensional model
of the lower jaw by performing a buccal measurement along the
recording path when the upper jaw and lower jaw are in a bite
position.
12. The methods according to claim 1 further comprising determining
an actual recording path of the dental camera by connecting centers
of the individual optical recordings.
13. The method according to claim 12, further comprising
determining a deviation between the actual recording path of the
dental camera and the virtual recording path disposed between two
virtual teeth and (i) displaying an error message when the
deviation exceeds a predetermined threshold and/or (ii) determining
a new control point for a new recording path.
14. The method according to claim 1, further comprising determining
one or more virtual gaps in the overall three-dimensional recording
and determining additional virtual control points and/or additional
virtual recording paths disposed between two virtual teeth for
measuring regions in the physical jaw corresponding to the
gaps.
15. The method according to claim 1, further comprising arranging
the first virtual control point in a middle of an occlusal surface
of a molar.
16. The method of claim 1, wherein a correctness of a position of
the first control point and/or second control point is confirmed by
user action.
17. A method of recording three-dimensional images of a physical
jaw using a dental camera, comprising: displaying a virtual
three-dimensional standard jaw model on a display device;
displaying a plurality of first and second virtual control points
on a plurality of first and second virtual teeth of the virtual
three-dimensional standard jaw model respectively; determining a
plurality of virtual recording paths each disposed between two
virtual teeth said plurality of virtual recording paths each
disposed between two virtual teeth are defined by a plurality of
visible paths with each visible path of the plurality of visible
paths disposed between one of the plurality of first virtual
control points on one of the plurality of first virtual teeth and
one of the plurality of second virtual control points on one of the
plurality of second virtual teeth; displaying said plurality of
virtual recording paths each disposed between two virtual teeth on
the three-dimensional standard jaw model; sequentially operating
the camera to automatically generate a plurality of
three-dimensional images of the physical jaw in succession along
portions of the physical jaw corresponding to the plurality of
virtual recording paths, by moving the dental camera, for each
virtual recording path of the plurality of virtual recording paths,
relative to the physical jaw and automatically recording the
plurality of three-dimensional images, for each virtual recording
path, at a constant frequency, the automatic recording at the
constant frequency starts from a portion of the physical jaw
corresponding to a first virtual tooth, follows a direction of the
virtual recording path, and ends at another portion of the physical
jaw corresponding to a second virtual tooth.
18. The method according to claim 17 further comprising acquiring
at least two clusters of occlusal, lingual or palatal and buccal
measurements and registering at least two clusters of the occlusal,
lingual or palatal, and buccal measurements together.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a National Phase application of International Application
No. PCT/EP2015/058767 filed Apr. 23, 2014, which claims the benefit
of and priority to German Application Ser. No. 102014207667.6,
filed on Apr. 23, 2014, which are herein incorporated by reference
for all purposes.
TECHNICAL FIELD
The invention relates to a method for performing an optical
three-dimensional recording by using a hand-held dental camera,
wherein the camera records a plurality of individual optical
recordings in succession during the measurement. The individual
three-dimensional optical recordings are then combined by means of
registration into an overall three-dimensional recording of a
dental subject to be measured.
BACKGROUND OF THE INVENTION
Multiple registration methods in which a plurality of individual
optical recordings are performed and a subsequent registration
ensues are known from prior art. During the registration,
coincident areas--what are known as overlapping areas--are
identified and registered together so that an overall recording is
formed from the individual optical recordings.
This measurement, what is known as an on-the-fly measurement, can
lead to an incorrect registration. This can, for example, be caused
by overlapping areas being too small, by recording errors, or by
interfering objects such as cheeks or tongues in the individual
recordings.
One disadvantage of this method is that the hand-held dental camera
is moved freely by the user without a user guidance during the
manual measurement. This can, therefore, result in some areas of
the subject being repeatedly measured unnecessarily, thereby
increasing the data volume to be registered and the recording time.
It is also possible for some areas of the subject to be left out
during the measurement, leading to gaps being created. These gaps
must then subsequently be filled by additional recording
sequences.
The object of the present invention is therefore to provide a
method that enables a reliable, complete and rapid measurement of
the subject with a repeatable registration situation.
SUMMARY OF THE INVENTION
The invention relates to a method for performing an optical
three-dimensional recording by using a hand-held dental camera,
wherein the camera automatically records a plurality of individual
optical recordings in succession at a set frequency during the
measurement. The individual three-dimensional optical recordings
are then combined by means of a registration method into an overall
recording of a dental subject to be measured. Before the
measurement is performed, a three-dimensional standard jaw model is
displayed by means of a display device, wherein a first control
point on the standard jaw model is displayed by means of the
display device. The hand-held camera is then positioned in relation
to the subject to be recorded in such a way that the camera points
at the first control point of the standard jaw model and records a
corresponding recording region of the dental subject in an optical
recording.
The camera therefore automatically records a plurality of
individual recordings during the measurement, for example at a
frequency of 18 Hz, wherein the hand-held camera is moved relative
to the subject. Therefore, the individual recordings do not need to
be triggered manually.
The optical recordings are measured by means of the dental camera
which, for example, can function according to a fringe projection
method. In the fringe projection method, the individual fringes
projected onto the subject are identified based on intensity,
color, polarization, coherence, phase, contrast, location or
duration. The 3D coordinates of the individual measuring points on
the subject are then calculated using a triangulation method. The
color encoding enables each of the color fringes to be
unambiguously identified based on a specific order of the color
fringes. For example, a slide or a grid can be used to generate a
fringe pattern.
Alternatively, a confocal measurement method may also be used to
record the individual three-dimensional recordings of the
subject.
During the measurement, the hand-held dental camera is moved
relative to the dental subject (such as a lower jaw or an upper
jaw), wherein the three-dimensional optical images are generated at
regular time intervals. The individual images can, for example, be
generated at a clock frequency between 10 Hz and 20 Hz. The
registration is performed by means of a computer which evaluates
the recordings recorded. The ICP registration process (Iterative
Closest Point algorithm) can be used as the registration method,
for example. This algorithm is a known process for registering
two-dimensional or three-dimensional subjects. The objective of
this method is to align two different 3D models of a subject with
one other at a minimal distance. To this end, different rotations
and translations are applied to corresponding pairs of points of
the two recordings to be registered, thereby minimizing a quadratic
error of the distances between the pairs of points. This iterative
convergence is performed until the two recordings coincide within
the overlapping area.
As an alternative or in addition, the registration can also take
place on the basis of the color of the recorded subject, the
surface curvature of the recorded subject or on the basis of
characteristic geometries of the subject. Given registration on the
basis of characteristic geometries, a pattern recognition algorithm
is used whereby the two recordings to be registered are searched
for a specific geometric pattern, such as for an occlusal surface
of a specific tooth.
The registration process can lead to registration errors if, for
example, the camera moves too quickly in relation to the subject,
resulting in the size of the overlapping area being insufficient.
Another reason could be that the autofocus of the digital camera is
not sharply set, thereby causing the subject to be indistinctly
imaged such that the recording quality of the image is
insufficient. An additional reason could be that movable objects
such as the tongue of the patient or a finger of the treating
dentist are recorded during measurement. Consequently, the
overlapping areas of the images do not correspond.
Given this process, a user guidance takes place before the
measurement is performed, wherein the first control point is
displayed by means of a display device on the three-dimensional
standard jaw model (which can be stored in a memory of a
computer).
The display device can, for example, be a monitor that is connected
to a computer. The standard jaw model can, for example, be
displayed semi-transparently, wherein the individual recordings as
well as the registered overall recording can be represented as an
opaque three-dimensional model in superposition with the standard
jaw model. The user can thereby visually identify in a simple
manner which areas of the jaw have already been measured.
The dental subject can also be an individual tooth, a group of
teeth, or a preparation for a tooth replacement part to be
implanted.
Therefore, the first control point can thereby be arranged as user
guidance in the area of the preparation in order to measure it
completely.
The standard jaw model can thereby be modified conditional upon
patient data. If, for example, specific teeth of the patient's jaw
to be measured (such as the back molars with the FDI umbers 18, 28,
38 or 48) are missing, these teeth will also be missing from the
standard jaw model. If it is known from the patient data that a
specific tooth has been repaired, the standard jaw model can also
have a standardized preparation. This enables the user to orient
himself more easily within the tooth situation to be measured.
The first control point on the standard jaw model is therefore
displayed for user guidance so that the user identifies in which
area of the jaw he should begin with the measurement.
The control point can be emphasized in color or graphically, for
example.
The control point can be represented in any number of ways, for
example as a point, as a red circle or as a cross.
An advantage of this method is that the user guidance enables a
repeatable measurement of the object and a reliable registration on
the standard jaw model by means of the display device due to the
fact that the subject can be measured in the same way following the
control points along the displayed recording paths.
A further advantage of this method is that--in contrast to an
on-the-fly measurement--the subject is not measured arbitrarily but
rather along the optimized recording paths, so that recording time
and data volumes are minimized.
A further advantage of this method is that a reliable global
registration is made possible, as all clusters are registered
relative to one another in a stable framework due to the optimized
recording paths.
Advantageously, the correctness of the position of the first
control point can be confirmed by a user action.
The user can thereby confirm the correctness of the position of the
first control point without putting the camera down.
Advantageously, the user can hold the dental camera steady on the
first control point, relative to the subject, for a defined period
of time until an acoustic, visual and/or haptic signal ensues as
feedback.
In this way, the dental camera can be held steady over the control
point, for example for a duration of 2 seconds. An acoustic, visual
and/or haptic signal can ensue as a feedback, for example by means
of an LED on the camera, by vibration or by a beep tone. The user
is thereby informed that the first control point has been
confirmed.
The velocity or the acceleration of the camera relative to the
subject can be determined using acceleration sensors in the camera,
or also by evaluating the individual recordings. In so doing, the
change in characteristic structures in the recordings is determined
and the velocity is determined therefrom.
The signal as feedback can, for example, ensue if the acceleration
or the velocity of the camera relative to the subject does not
exceed a specific threshold value for a specified duration.
Advantageously, the user can confirm the first control point by
actuating a button on the camera.
In so doing, the user can confirm the first control point without
taking his hand from the camera.
Advantageously, the user can confirm the first control point by
performing a gesture with the camera.
A gesture can, for example, be a single or double motion of the
hand-held camera to the right. This is then interpreted as a
command to confirm the first control point and to mark it
accordingly in the software at the display device.
Advantageously, the user can confirm the first control point by
means of a voice command in that the voice command is recorded in
an audio recording and detected by means of voice recognition.
In this way the user can therefore confirm the control point by
saying the respective voice command.
Advantageously, the user can confirm the first control point by
operating an input means such as a mouse or a keyboard.
In this way the user can therefore confirm the control point by
means of the input means which are connected to the computer.
Advantageously, the dental subject can be an entire upper jaw
and/or a lower jaw.
The dental subject can therefore be the entire upper jaw, the
entire lower jaw, or also an individual tooth, a group of teeth or
a preparation.
Advantageously, the first control point for the measurement of an
entire upper or lower jaw can be arranged in the middle of an
occlusal surface of a molar which is located on a left end or on a
right end of the standard jaw model.
As a result the first control point can, for example, be in the
center of the occlusal surface of a molar 18 (top right), of a
molar 28 (top right) for the top jaw, or of a molar 48 (bottom
right), or of a molar 38 (bottom left) of a bottom jaw, in
accordance with the FDI ordontogram. This control point is
therefore already defined prior to the measurement on the standard
jaw model.
Advantageously, the user can shift the position of the defined
first control point relative to the standard jaw model using an
input means, thereby redefining said position.
Therefore, the user can thereby shift the first control point by
means of an input means (such as a mouse) and adjust it to the
actual tooth situation. For example, in the event that the back
molars 18, 28, 48 or 38 according to the FDI ordontogram are
missing. An additional reason for the adjustment could be
measurements of the actual jaw that deviate from the standard jaw
model.
Advantageously, in addition to the first control point a second
control point can be defined on an opposing end of the jaw to be
measured and can be displayed by means of the display device,
wherein a first recording path is defined between the first control
point and the second control point, which path is displayed on the
standard jaw model by means of the display device.
As a result, a recording path is defined between a first control
point on the molar 18 or 48 and a second control point on the molar
28 or 38, which path is able to pass through the tooth centers of
the individual teeth in the standard jaw model. The tooth centers
are thereby defined as centers of the occlusal surfaces of the
molars or as the middle of the incisal edges of the incisors. This
recording path then corresponds to the optimum measurement movement
of the camera for the occlusal measurement. The graphically
displayed recording path serves as a user guidance for the user
during the measurement.
Advantageously, an occlusal measurement can be performed from an
occlusal direction relative to the jaw, wherein the manually held
dental camera is moved along the displayed first recording path
until the second control point is reached.
In this way the jaw is therefore measured from an occlusal
direction.
Advantageously, the correctness of the position of the second
control point can be confirmed by a user action.
In this way, the second control point can also be confirmed by one
of the actions described above, such as holding the camera steady
or by activating a button on the camera.
Advantageously, a lingual or a palatal measurement can be performed
of tooth surfaces lying in an oral direction of the upper jaw or of
the lower jaw as a subject. In so doing, a third control point is
defined on the opposing end of the jaw originating from the second
control point, wherein a second recording path is defined between
the second control point and the third control point and displayed
by means of the display device. The hand-held camera is then moved
along the second recording path during the measurement, wherein the
position of the third recording point is confirmed by a user
action. The third control point can thereby have the same position
as the first control point.
As a result, a lingual or palatal measurement of the upper jaw or
of the lower jaw is performed along the second recording path as
user guidance.
Advantageously, a buccal measurement can be performed from a buccal
direction, wherein in a first step a first buccal measurement is
performed originating from a fourth control point on a first end of
the jaw arch to the middle of the jaw arch and furthermore to a
fifth control point along a third recording path, wherein
subsequently in a second step a second buccal measurement is
performed originating from a sixth control point on a second
opposing end of the jaw arch to the middle of the jaw arch and
furthermore to a seventh control point along a fourth recording
path, which is displayed by means of the display device.
As a result, a buccal measurement of the upper jaw or the lower jaw
is performed along the third and the fourth recording path as user
guidance.
Advantageously, a first cluster from the first buccal measurement
and a second cluster from the second buccal measurement can be
registered relative to one another using a shared overlapping area
in the middle of the jaw arch.
In this way the two clusters are registered relative to the overall
recording of the entire jaw arch.
Advantageously, at least one fringe recording sequence can be
performed in a buccal direction, perpendicular to a jaw curve of
the jaw arch to be measured along a fifth recording path which is
displayed by means of the display device prior to the measurement
of this fringe recording sequence. In so doing, the clusters
previously generated from the occlusal measurement, the lingual
measurement and/or the buccal measurement are linked to one
another, thereby improving the registration.
Due to the measuring of the fringe recording sequence, the image
data of the clusters from the occlusal measurement, the lingual
measurement and/or the buccal measurement are linked to one
another. To improve the registration, two or three fringe recording
sequences can also be performed, for example top right, middle, top
left for the upper jaw or bottom right, middle, bottom left for the
lower jaw.
Advantageously, a bite block registration can be performed, wherein
a first three-dimensional model of the upper jaw is registered
relative to a second three-dimensional model of the lower jaw. In
so doing, a buccal recording sequence is measured in a bite block
position along a seventh recording path which is displayed between
the corresponding control points by means of the display
device.
In this way, therefore, a bite block registration is performed,
wherein the seventh recording path (which is depicted by means of
the display device) serves as a user guidance.
The jaw curves determined for the upper jaw and the lower jaw can
also be used for the bite block registration in that the two jaw
curves are aligned parallel to one another. The buccal recording
sequence is then used to perform a finer registration of the upper
jaw to the lower jaw.
Advantageously, an actual recording path of the camera can be
determined which is formed by the projections of the centers of the
individual recordings along a camera axis on a surface of the
subject, wherein the actual recording path of the camera is
displayed by means of the display device.
In so doing, a deviation between the actual recording path and the
planned recording path can be determined during the
measurement.
In the event that this deviation falls below a defined threshold
value, an error message can be displayed by means of the display
device. The user can then be asked to continue the measurement at a
new control point.
The actual recording path of the camera can therefore be
determined, wherein the centers of the recording areas of the
recordings are graphically represented and connected. This allows
the user to easily follow the deviation between the actual
recording path, the camera and the planned first recording
path.
To improve the registration, the determined jaw curve from the
occlusal recording, which connects the actual tooth centers of the
teeth, can be used for what is known as an outlier rejection.
Structures which are arranged outside a defined distance relative
to the jaw curve, for example, can be hidden in the occlusal
measurement.
Only structures up to the jaw curve are considered for the lingual
measurement, and structures which are arranged in a buccal
direction behind the jaw curve are hidden.
Only structures up to the jaw curve are considered for the buccal
measurement, and structures which are arranged in a lingual
direction behind the jaw curve are hidden.
In this way, therefore, interfering objects such as the tongue of
the patient or finger of the treating dentist are hidden due to the
fact that they are arranged further away from the jaw curve than
the tooth substance of the teeth to be recorded.
Advantageously, the standard jaw model in superposition with the
previously registered individual recordings can be pivoted,
depending on a recording direction of the camera, in such a way
that surfaces of the subject to be recorded are displayed, wherein
the standard jaw model is displayed in the occlusal direction
during the occlusal measurement, wherein during the lingual
measurement the standard jaw model is pivoted such that the lingual
surfaces to be recorded and the previously recorded occlusal
surfaces of the teeth are visible, wherein during the buccal
measurement the standard jaw model is pivoted such that the buccal
surfaces to be recorded and the previously recorded occlusal
surfaces of the teeth are visible.
In this way, the user can better orient himself on the standard jaw
model during the measurement. This is due to the fact that the
surfaces to be recorded are clearly displayed.
Advantageously, with the aid of a computer it is possible to
automatically determine in which areas the registered overall
recording of the subject has gaps, wherein additional control
points and/or additional recording paths are displayed in
succession in these areas on the standard jaw model for user
guidance.
As a result, the automatic user guidance takes place control point
for control point for as long as it takes for all gaps to be filled
and the overall recording to be complete without gaps.
Advantageously, specific areas of the subject which are to be
completely measured and which contain a preparation, for example,
can be defined on the standard jaw model before the measurement,
wherein it is checked with the aid of a computer whether these
areas have been completely measured or whether they have gaps,
wherein--in the event that these areas have gaps--additional
control points and/or additional recording paths are displayed on
the standard jaw model in order to measure these areas
completely.
In this way it is ensured that significant areas of the subject are
measured completely and without gaps, for example for the planning
of tooth replacement parts.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained with reference to the drawings. The
figures depict the following:
FIG. 1 a sketch to illustrate the present method for performing an
optical three-dimensional recording;
FIG. 2 a sketch of a standard jaw model of an upper jaw for an
occlusal measurement;
FIG. 3 a sketch of a standard jaw model of an upper jaw for a
lingual measurement;
FIG. 4 a sketch of a standard jaw model of an upper jaw for a first
step of a buccal measurement;
FIG. 5 a sketch of a standard jaw model of an upper jaw for a
second step of a buccal measurement;
FIG. 6 a sketch to illustrate a plurality of fringe recording
sequences;
FIG. 7 a sketch to illustrate a linking of the different
clusters;
FIG. 8 a sketch to illustrate a bite block registration.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 depicts a sketch to illustrate the present invention of an
optical three-dimensional recording of a dental subject 1 to be
measured, such as a bottom jaw, by means of a hand-held dental
camera 2 which is pivoted around the dental subject 1 along a
trajectory 3. The three-dimensional optical recordings 4, which are
represented in the form of rectangles, are measured by means of the
dental camera 2 which is pivoted along the trajectory 3 around the
subject 1 during the measurement. The camera 2 is a hand-held
camera which works using a fringe projection method. The recordings
4 are registered relative to one another using the overlapping
areas 5 which are shown as dashed lines, thereby generating an
overall recording of the object 1. Prior to the measurement being
performed, a three-dimensional standard jaw model 7 is displayed by
means of a display device 6 such as a monitor, which model
corresponds in its measurements to an average jaw arch. In so
doing, a first control point 10 is displayed on the standard jaw
model of the lower jaw, bottom right, on the left end of the
standard jaw model 7 in the middle of an occlusal surface 8 of the
back molar 9 with the FDI number 38, bottom left. The control point
10 is represented schematically as a black circle. The user then
moves the dental camera in the area of the molar 9 so that the
camera records the first control point 10. The camera 2 is then
held steady over the first control point for a defined period of
time until an acoustic, visual and/or haptic signal ensues as a
feedback and the position of the first control point is thereby
confirmed. The first control point 10 can also be confirmed by
operating a button 11 on the camera 2.
Alternatively, the control point 10 can also be confirmed by means
of the input means, such as a keyboard 12 and a mouse 13, which are
connected to a computer 14.
A second control point 15 and a first recording path 16 are
displayed in addition to the first control point. The second
control point is thereby arranged on the opposing end of the jaw
arch on the back molar 17 with the FDI number 48. The recording
path 16 thereby runs through the tooth centers 18 of the individual
teeth 19 of the standard jaw model 7. The displayed recording path
serves as a user guidance for the user in order to display which
areas of subject 1 are to be measured.
For orientation, the standard jaw model 7 can be pivoted such that
buccal surfaces 20 of a recording area 23 (which is shown as a
dashed line) that are to be recorded are displayed in the
foreground, wherein the previously measured occlusal surfaces of
the subjects are also visible.
In this way, the line of sight on the standard jaw model 7 is
changed during the measurement simultaneous with the movement of
the camera 2 so that the user, such as the dentist, can orient
himself more easily within the tooth situation.
FIG. 2 depicts a sketch of a standard jaw model 7 of an upper jaw,
wherein the first recording path 16 originating from a first
control point 10 (top right) on a first molar 30 with the FDI
number 37 runs up to the second control point 15 on the opposing
end of the jaw arch on the second molar 31 with the FDI number 47.
The recording path 16 thereby runs through the tooth centers 18 of
the individual teeth 19 of the standard jaw model 7. The dental
camera 2 is therefore moved such that a center of the recordings 4
coincides with the recording path 16. In this way, an occlusal
measurement is therefore carried out from the occlusal direction 21
of the top jaw.
FIG. 3 depicts a sketch to illustrate a lingual measurement of the
upper jaw from a lingual or oral direction 40, which is represented
by an arrow. The camera 2 is then positioned relative to the
subject 1 in such a way that the recording from this direction 40
is facilitated, as indicated in FIG. 3. The lingual measurement is
carried out along a second recording path 41 originating from the
second control point 15 toward a third control point 42. Therefore,
the inside tooth surfaces of the upper jaw are measured with the
lingual measurement.
FIG. 4 depicts a sketch to illustrate a buccal measurement from a
buccal direction 50, wherein a camera 2 is pivoted around the jaw
in such a way that the buccal tooth surfaces 52 and the labial
tooth surfaces 53 are measured. The teeth 54 are therefore not
measured in the first step. The third recording path 51 thereby
runs originating from a fourth control point 55 at the molar with
the FDI number 37 across a middle 56 of the jaw arch up to a fifth
control point 57. The position of the fourth control point 55 can
thereby correspond to the position of the control point 42 and the
control point 10.
FIG. 5 depicts a second buccal measurement originating from a sixth
control point 60 across the middle 56 of the jaw arch to a seventh
control point 61 along a fourth recording path 62. A first cluster
from the first buccal measurement from FIG. 4 and a second cluster
from the second buccal measurement from FIG. 5 are then registered
relative to one another using a shared overlapping area 63 in the
middle of the jaw arch.
FIG. 6 depicts a sketch to illustrate a first fringe recording
sequence in buccal direction 70 perpendicular to a jaw curve 71 of
the jaw arch to be measured along a fifth recording path 72 between
the control points 73. The fifth recording path 72 thereby runs in
the area of a molar with the FDI number 14. In addition, a second
fringe recording sequence is performed in the labial direction 75
along a sixth recording path 74 in the area of the incisor with the
FDI number 11, and a third fringe recording sequence is performed
in the buccal direction 77 along the seventh recording path 76 in
the area of the molar with the FDI number 24.
FIG. 7 depicts a sketch which is to illustrate that a first cluster
80 from the occlusal measurement in FIG. 2, a second cluster 81
from the lingual measurement in FIG. 3 and a third cluster 82 from
the buccal direction in FIG. 4 and FIG. 5 are linked to each other
by the fourth cluster 83 of the first fringe recording sequence
from FIG. 6, as well as by the fifth cluster 84 of the second
fringe recording sequence and the sixth cluster 85 of the third
fringe recording sequence. The linkage points 86 are indicated by
the crosses.
FIG. 8 depicts a sketch to illustrate a bite block registration,
wherein a first three-dimensional model 90 of the upper jaw is
registered relative to a second three-dimensional model 91 of the
lower jaw. In this way, a first buccal recording sequence is
performed along a recording path 92 between the control points 93
and 94, and a second buccal recording sequence is performed along
the recording path 95 between a control point 96 and a control
point 97. The first buccal recording sequence thereby runs in the
area of the teeth with the FDI numbers 14 and 44. The second buccal
recording sequence runs in the area of the teeth with the FDI
numbers 24 and 34.
REFERENCE CHARACTERS
1 Subject 2 Camera 3 Trajectory 4 Recording 5 Overlapping area 6
Display device 7 Standard jaw model 8 Occlusal surface 9 Molar 10
Control point 11 Button 12 Keyboard 13 Mouse 14 Computer 15 Second
control point 16 First recording path 17 Back molar 18 Tooth
centers 19 Teeth 20 Buccal surfaces 21 Occlusal direction 22 Buccal
direction 23 Recording area 30 First molar 31 Second molar 40
Direction 41 Recording path 50 Buccal direction 51 Third recording
path 52 Buccal tooth surface 53 Labial tooth surface 54 Teeth 55
Fourth control point 56 Middle 57 Fifth control point 60 Sixth
control point 61 Seventh control point 62 Third recording path 63
Overlapping area 70 Direction 71 Jaw curve 72 Fifth recording path
73 Control point 74 Sixth recording path 75 Seventh recording path
76 Direction 80 First cluster 81 Second cluster 82 Third cluster 83
Fourth cluster 84 Fifth cluster 85 Sixth cluster 86 Linkage point
90 First three-dimensional model 91 Second three-dimensional model
92 Recording path 93 Control point 94 Control point 95 Recording
path 96 Control point 97 Control point
* * * * *